How to clean windows without streaks, inside and out

Step by step: how to clean windows without streaks, inside and out

Safety first. Never mix an ammonia-based glass cleaner or vinegar with bleach, which releases toxic gas. For outside glass above the ground floor, use tilt-in sashes or an extension pole where you can, and on a stepladder lock the spreaders and do not stand on the top step.

1. 1

   Pick a cloudy day or a shaded side

   Sun dries the cleaning solution on the glass before you can squeegee it off, and that is the main cause of streaks. Clean on an overcast day, or follow the shade around the house.

2. 2

   Clear the sill and frame first

   Lay a towel below the window. Vacuum or brush the sill, corners and frame to remove dust, dead insects and cobwebs, then wipe the frame with a damp cloth. If the screen comes out, take it out now and wash it separately.

3. 3

   Mix your solution

   Stir a short squeeze of dish soap, about a 10 second pour, into 2 to 3 gallons of water. Or fill a spray bottle with equal parts white vinegar and water. Either works; soapy water lets the squeegee glide better on dirty outside glass.

4. 4

   Wash the glass from the top down

   Dip the scrubber or sponge, squeeze out most of the water, and wash the whole pane with up-and-down and side-to-side strokes using light pressure. Very dirty outside glass may need a second wash. Do not let the solution run onto wood frames and sit.

5. 5

   Break the water line at the top

   Wipe a dry cloth along the top edge and the sides of the glass to make a dry strip about an inch wide. This gives the squeegee a clean place to start and stops drips from running back down.

6. 6

   Squeegee in straight strokes

   Start in a top corner and pull the squeegee straight down to the bottom. Wipe the blade on a cloth, then start the next stroke slightly overlapping the first. Tilt the blade a little so it pushes water toward the part of the glass you have not done yet.

7. 7

   Detail the edges and sill

   Use a clean, dry part of a microfiber cloth to wipe the edges where the squeegee could not reach, and soak up the water that pools at the bottom. Switch to a fresh cloth as soon as one gets damp, or it will leave lint and streaks.

8. 8

   Do the outside the same way

   On tilt-wash double-hung windows, tilt the sash in and clean the outside from indoors. Otherwise, clean from the ground with a scrubber and squeegee on an extension pole. Check each pane from inside and outside at an angle to find any streak, which tells you which side it is on.

Which window cleaner works best?

A little dish soap in water and a squeegee is what most professionals use, and diluted vinegar works well for indoor glass. Store-bought glass cleaner is fine for small panes and mirrors, as long as you check what your window maker allows.

Andersen suggests 2 to 3 gallons of water with a 10 second squeeze of dish detergent, or equal parts vinegar and water, and advises against razor blades, abrasive cleaners, solvents and pressure washing. Simonton recommends a mix of 30% white vinegar and 70% water for routine glass cleaning and says ammonia-free glass cleaners also work well.

How to clean windows without streaks

Streaks come from solution drying on the glass, dirty or damp cloths, and too much soap. Fix those three and most windows come out clear.

• Work in shade. Marvin advises against cleaning glass in direct sunlight, especially tinted and coated glass.
• Wipe the squeegee blade after every stroke and replace the rubber when it is nicked.
• Change to a dry cloth for edge detailing; a damp cloth only moves water around.
• Do not hose windows down to rinse them. Andersen notes the minerals in tap water leave spots behind.
• Skip newspaper. The ink can bleed onto and discolor painted or light-colored frames.
• For white mineral spots from sprinklers, see our guide to removing hard water stains, and test on a corner first if your glass has a special coating.

Cleaning second-story windows safely

Clean upper windows from inside wherever possible, and hire a professional for anything you cannot reach comfortably. A fall from a ladder is a far bigger risk than a streaky window.

• Many double-hung and casement windows tilt or swing so you can reach the outside glass from indoors. Check your window’s manual for how to release the sash.
• An extension pole with a scrubber and squeegee head reaches most second-floor glass from the ground.
• If you use a stepladder, OSHA’s stepladder fact sheet lists the hazards to avoid: unlocked spreaders, uneven or slippery ground, standing on the top step or cap, and reaching outside the side rails.

Mistakes to avoid

• Washing windows in full sun, so the solution dries into streaks before you squeegee.
• Adding a big squirt of soap, which leaves a film that is hard to rinse off.
• Using a razor blade or scouring pad on stuck-on spots and scratching the glass.
• Drying with a cloth that is already damp or linty.
• Leaving water standing on wood frames and sills.